#include<bits/stdc++.h>

int main()
{
	long long int n,sum=0,i,a,b,k;
	scanf("%lld%lld%lld",&a,&b,&n);
    if(n<=a) sum=1;
	 k=a*5+b*2;
      if(n/k>0) sum+=7*(n/k);
      n=n%k;
      if(n<=a*5)
       {
        sum+=(n+a-1)/a;
	   }
	   else {
	   	n=n-a*5;
	   	if(n<=b) sum+=6;
	   	    else sum+=7;
	   }
	 
	 printf("%lld",sum);
	 return 0;
}

#include<bits/stdc++.h>

int main()
{
	long long int n,sum=0,i,a,b,k;
	scanf("%lld%lld%lld",&a,&b,&n);
    if(n<=a) sum=1;
     else
	 {k=a*5+b*2;
     if(n/k>0) sum+=7*(n/k);
     n=n%k;
     if(n<=a*5)
       {
        sum+=(n+a-1)/a;
	   }
	   else {
	   	n=n-a*5;
	   	if(n<=b) sum+=6;
	   	  else sum+=7;
	   }
	 } 
	 printf("%lld",sum);
	 return 0;
}